Chelated beta dicarbonyl compounds

ABSTRACT

Beta dicarbonyl compounds are prepared by reacting an enol ester with aluminum chloride in the presence of an inert solvent at a temperature range of 20* to 50*C. An isopropenyl ester of an aliphatic fatty acid is used to prepare beta-diketone and a vinyl ester is used to prepare beta keto aldehyde. When reacted with any of several metals the dicarbonyl compounds form chelates.

United States Patent 1191 1 1111 3,919,275

Rothman et al. Nov. 11, 1975 [5 CHELATED BETA DICARBONYL 2178670693/1957 Kundiger et 61 .1 260/429 1x COMPOUNDS 2.837.57l 6/1958 Conover260/4381 x 310821171 3/l963 Hartle et 111. 2611/4381 x [75] n r Edward &R hm r h Hills: 3.242.145 3/[966 Martin .1 260/429 x Gordon G. Moore.Willow Grove 3.3561731 l2/l967 Nilsson .1 260/4381 X both of Pa. 0 OTHERPUBLICATIONS [73] Assrgnee: The Umted Stetes Of America Moshier et 11L,Gas Chromatography of Metal Cheg f l a i of lates Pergamon Press. Oxfordpp. I38 to I49. gm'mm Chemical Abstracts. v61. 4, l573lb (1966). [22]Filed: Jan. 12. I973 J.A.C.S.. Vol. 72 3635-3642 (l950).

[21] Appl. No: 323.021 1 2 1 Prmmr b\'un1111r'r-Helen M S. Sneed RelatedApplication Data Aim/71v Agent. or Fir/r1--M. Howard Silverstein; Max[62} 011151611 or 561 N6 41.57:. May 211 19711. D. Hensley; William EScott abandoned.

[57] ABSTRACT [52] US. Cl. 260/438.l; 260/586. 260/596 1511 1111. (:1.c071 1/03 Beta (Carbon/1. compofnds i f b} cactmg [58] Field of Search H260/4381 429 J, 596 an enol ester wrth alummurn chlorlde 1n the presence260/586 of an mert solvent at a temperature range of 20 to 50C. Anlsopropenyl ester of an ahphatrc fatty and 1s used to preparebeta-diketone and a vinyl ester is used [56] References cued to preparebeta keto aldehyde. When reacted with an UNlTED STATES PATENTS ofseveral metals the dicarbonyl compounds form che- Z.2()8.253 7/]940Flenner et all 260/438] lates 2.2232932 12/1940 Toune 260/4381 X2.3951400 3/[946 Boese et 111. 360/586 2 Claims, N0 Drawmgs CHELATEDBETA DICARBONYL COMPOUNDS A non-exclusive, irrevocable, royalty-freelicense in the invention herein described, throughout the world for allpurposes of the United States Government, with the power to grantsublicenses for such purposes, is hereby granted to the Government ofthe United States of America.

This application is a division of application Ser. No. 4l,573, filed May28, 1970, now abandoned.

This invention relates to a novel and facile preparation of betadicarbonyl compounds and more particularly to the isomerization of vinylesters and the more deep-seated alteration of isopropenyl esters bymeans of aluminum chloride catalysis to form beta ketoaldehydes in theformer instance and beta diketones in the latter instance.

The dicarbonyl compounds of this invention form useful complex salts ofthe type generally known as chelate compounds when reacted with any ofseveral metals. The metallo-chelates are useful as catalysts. Thedicarbonyl compounds are used as scavengers of metallic ions inprocesses such as ore concentration and separation of constituentmetals. For example, the copper chelate derivatives of the diketonesformed by the reaction of vinyl stearate with aluminum chloride aresoluble in organic solvents and the copper chelates are separable bychromatography in benzene or chloroform solution on inorganic supports.

in general, according to this invention an isopropenyl ester of analiphatic fatty acid, or alternatively a vinyl ester of an aliphaticfatty acid, is diluted with an inert hydrocarbon diluent and treatedwith 0.2 to 1.0 moles of anhydrous aluminum chloride at about from roomtemperature to 45C., for about half an hour, after which the aluminumchloride is destroyed with aqueous dilute hydrochloric acid, and theproducts are isolated by solvent extraction. It is often convenient toconvert the products to the copper chelates to facilitate thepurification of product since the metal chelates are wellcrystallized,sharp-melting compounds. Typically, the chelates are distinctly colored,e.g. distearoylmethane and dipalmitoylmethane are lilac colored, andformylstearoylmethane is blue-gray.

Side reactions are of no significance under the conditions of thereaction. it is to be emphasized that the diketone products aresymmetrical diketones and not the derivatives RCOCH CO=CH obtained byisomerizations previously reported [J. Org. Chem 3 l 628( 1966)].

The reaction of the isopropenyl esters is illustrated by the followingequation:

-continued R u- CNHI'H Is BI- n ss The chelate formation is illustratedfor distearoyl methane in equation 2;

In our experience the similar reaction of e.g. vinyl stearate gives notonly the expected beta keto aldehyde [1, but also, distearoylmethane I,see equation 3.

The advantages of the present invention include the simplicity of theroute whereby valuable diketones are obtained in a single step fromvinyl and isopropenyl esters, and a process that is generally applicablewith enol esters from that of acetic acid (C to that of stearic acid (Cwithout the need of high temperatures or vapor phase conditions.

The following examples illustrate the invention but are not intended tohave a limiting effect on its scope.

EXAMPLE i Distearoylmethane (heptatriacontane -l8,30-dione) lsopropenylstearate, l9 g., (0.06 mole) in 25 ml. of hexane was treated withaluminum chloride, 8.5 g., (0.06 mole) with occasional cooling in awaterbath to keep temperature below 40C. After stirring 0.5 hr. at 40C.the mixture was poured into a mixture of dilute hydrochloric acid andmethylene chloride to destroy the catalyst and extract the product.After separation of the organic layer and evaporation of the methylenechloride the diketone was crystallized directly from methanol to givewhite plates m.p. 77.377.8, UV max. (isooctane) 273 my. (E 12000), ir6.24;. (chloroform), NMR 3.54, 5.415. The copper chelate deriva tive wasprepared by mixing hot alcoholic solutions of the diketone and cupricacetate. Crystallization of the lilac-colored crystalline product gavethe chelate m.p. ll3.2-l C. The chelate may be reconverted to the freediketone by shaking its chloroform solution with dilute aqueoushydrochloric acid and evaporating the chloroform layer.

EXAMPLE ll Dipalmitoylmethane Vinyl palmitate, 145 gram (0.51 mole)dissolved in 400 mls of olefin-free hexane was heated, portionwise with85 g. (0.6 mole) of anhydrous aluminum chloride added at such a ratethat the evolved heat did not allow the temperature to rise more thanabout C. The mixture was then refluxed for an hour, cooled, and pouredinto a mixture of l liter of water, 300 ml. of concentrated hydrochloricacid and 1.5 l. of methylene chloride. The methylene chloride layer wasseparated (methanol assisted in controlling emulsion problems) dried,and the solvent was evaporated. The residue, dissolved in hot ethanol,was treated with hot aqueous cupric acetate in slight access whereupon120 g. of mixed copper chelates separated and were collected on afilter. Chromatography on magnesium silicate gave via hot benzeneelution 50 g. of the lilac colored copper chelate derivative ofdipalmitoylmethane m.p. l l 3-l 14C., infrared maxima (in chloroform) at1405 and 1560 waves per centimeter. Further elution with lzl methylenechloride/ether gave the blue colored copper chelate derivative offormylpalmitoylmethane m.p. lO6l()8C.

EXAMPLE ll] In a manner similar to Example I, isopropenyl octanoate wasconverted to dioctanoyl methane m.p. 20-2lC., UV 274 my (isooctane) (E=lL000), copper chelate derivative, m.p. ll0.2-l l0.7C., ir 1350, 1410,1458, 1554 cm (CHCl EXAMPLE IV In a manner similar to example I] vinyllaurate was converted to dilauroylmethane; copper chelate, m.p.l07l()9C.; and to lauroylformylmethane, copper chelate m.p. l0OlO2C.

EXAMPLE V 2. The copper chelate of stearoylformylmethane.

1. THE COPPER CHELATE OF LAUROYLFORMYLMETHANE.
 2. THE COPPER CHELATE OFSTEAROYLFORMYLMETHANE.